1. Technical Field
The invention relates to an inductor device and a semiconductor device and relates to, for example, a technology which can be used for an inductor device, in which an inductance value is variable, and a semiconductor device.
2. Related Art
An inductor is an element which is important in configuring an analog circuit, for example, a wireless communication circuit. In recent years, a wireless communication circuit which handles a plurality of frequency bands is desired. In order to realize such a wireless communication circuit, it is desirable to cause the inductance value of an inductor to be variable. In contrast, for example, research by Kenichi Okada et al., “Reconfigurable RF Circuit Technology Using MEMS Variable Inductor”, IEICE Technical Report ED2005-116 OME2005-42 discloses that it is possible to change the inductance value of an inductor by vertically moving a conductor plate which is disposed on the upper side of the inductor.
In addition, Japanese Unexamined Patent Application Publication No. 8-204139 discloses a technology below. First, an insulation layer is formed on a substrate, and an inductor and fixed electrodes are formed on the insulation layer. Further, a movable electrode is disposed to cover the inductor and the fixed electrodes. The ends of the movable electrode are curved toward the substrate and are fixed to the substrate.
In a technology disclosed in Japanese Unexamined Patent Application Publication No. 8-204139, the inductance value of an inductor is determined based on the distance between the movable electrode and the inductor. Therefore, it is necessary to control the distance between the movable electrode and the inductor with high precision. However, in a case of a plate shape, such as a conductor plate, it is difficult to perform vertical operation using an actuator due to air resistance or the delay of an operation occurs. Due to such malfunction and delay, defects occur with regard to control of a variable inductor, and thus circuit characteristics deteriorate. Other problems and new characteristics will be apparent based on the description of the specification and the accompanying drawings.